The Digger Wasp

The Digger wasp (Sphex funerarius) with up to 2.5 cm body length of is one of the largest Hymenoptera (wasps, bees, ants, etc). It occurs in southern Europe, northern Africa and Asia to Mongolia. This year we have seen this interesting species quite often in our garden.

The name wasp is applied to all members of the Hymenoptera except the bees and the ants. Accordingly the wasps are a highly diversified (and also very interesting!) insect group. On Naxos occurs a wide variety of Hymenoptera, including a number of digger wasp species. The digger wasps are characterized by their distinctive reproductive behavior: They lay their eggs on insects and spiders on which the larvae feed. The digger wasp catches and stuns its prey and deposits it as food for their larvae in underground nests. Sphex funerarius, one of the largest species, hunts bush crickets and grasshoppers. In contrast to most other species it stores several grasshoppers in the same nest. It digs a 15 cm long main corridor, whith a number of brood chambers branching sideways off, in each of which one of the prey is stored with an egg. The larvae hatch after three or four days and need 18 days to pupation; they hatch after another 24 days as adult (imago).

The digger waps Sphex funerarius can reach a size of 2.5 cm. It is black with an orange-red band on the anterior abdomen. In contrast to most Hymenoptera, digger wasps do not fold their wings.

Sphex funerarius catches bush crickets and grasshoppers as food for their larvae, which they stun with several stings. As you can see, the wasp can overwhelm animals, which are considerably larger than themselves (here, a Great Green Bush Cricket). The prey is dragged by the wasp to the nest, which holds it with its mandibles (jaws) at the basis of the antennae. It was not easy to take a picture of the wasp in this activity because it drags the bush cricket with incredible speed, and that over a distance of about 15 m straight across our garden.

When it arrives at the nest, the wasp puts the prey down at a short distance of the entrance, and crawls first into the nest to control it and dig some more sand out if necessary.

Here it drags the bush cricket to the entrance.

It pulls the prey again by its antennae, walking backwards.

Quickly predator and prey disappear into the nest. The wasps deposits the prey in one of the brood chambers and lays an egg on it. In a few days the larva hatches and starts feeding on the living, but permanently stunned prey.

Once again the wasp in front of its nest. During all the summer the digger wasps catch in this way a quite large number of bush crickets and grasshoppers.

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